Brendan, I hope your punt pays off.
I notice that you have not been able to state what specifically in Tesla's financials indicates to you that the shareprice will decline, that let you to decide to short. Also you have not indicated a timeline for this investment? With the vagueness provided this allows you to be always right if the share price actually declines, for example if Musk announces tomorrow that he has built a rocket to send him to Mars next month and the shareprice falls would you claim a victory? What I am saying, is if the shareprice falls for whatever reason you will claim a victory but if the share price increases, it is a mania and the market is wrong?
In terms of the floor you have set indicates a 63% price decrease. I want to highlight that is a shock of -63%, this is over double what the Federal Reserve stress Equities under a Severely Adverse (Worse than 2008 Financial Crisis) in stress testing. That shock of 30% can be thought of as a 6 month move in Equity prices. The 63%, I have not done analysis but I would suggest that is 1-2 year move, implying you are going to keep the position open for 2 years. Can you clarify how long you think it will take Tesla to go to $200?
There are two options for a move to $200 / -63%
1. There is a market wide decrease in Equities + Idiosyncratic under performance by Tesla. This would still require a significant decrease in the wider Equity market. If this is your belief then hedge your equity portfolio.
2. This decrease is a purely idiosyncratic event contained to Tesla only and no market contagion. In the case of an event causing a 63% decrease in share price, it is probably going to go to 0.
In summary you might as well set the level to $0 or actually set it to a level that is actually achievable from general price corrections.
I have not looked into Tesla share price in any detail but the 12 month low is 178.97 and the 12 month high is 537.32. That doesn't make Brendan's floor look stupid. You mention the FED stress test but that test is based on the market, not an individual share. Ask the fed what their stress test would be for a bank holding a huge position in a single share and ask them if a 63% price decrease is ludicrous.....